影响刀具使用寿命的因素有哪些？
参考答案：刀具磨损的原因有磨粒磨损、粘结磨损、扩散磨损、相变磨损、氧化磨损、其它磨损。
96. In this novel, he is ____ as a hero, actually he is a coward.
A．explained
B．narrated
C．described
D．Recounted
“杏林春暖”出自：（）
A.原始社会
B.三国时期
C.明代
D.清代
